In recent years, portable liquid crystal terminals represented by smartphones and other liquid crystal display devices have been equipped with a touch panel function. In the related art, the above-described liquid crystal display device equipped with a touch panel function was mainly an external liquid crystal display device including a touch panel attached onto the liquid crystal display device.
Since the external liquid crystal display device is produced by separately manufacturing a liquid crystal display device and a touch panel, and then integrating them together, even when any one of the components does not work properly, the other component can still be used, and thus the yield is excellent, but there has been a problem in that the thickness or weight increases.
To solve the above-described problem (with the thickness or weight) of the external liquid crystal display device, a so-called on-cell liquid crystal display device produced by incorporating a touch panel between a liquid crystal element and a polarization plate in the liquid crystal display device has emerged.
In addition, more recently, as a liquid crystal display device having a smaller thickness or weight than the on-cell liquid crystal display device, a so-called in-cell liquid crystal display device produced by incorporating a touch function into a liquid crystal element has begun to be developed (PTLs 1 and 2).